The compound parabolic concentrator, CPC, is a form of a non-imaging concentrating optic ie. a family of optical components that concentrate light without forming an image. CPCs are described and documented in the text “Nonimaging Optics” by Roland Winston, et al hereby incorporated by reference. The CPC has a variety of applications ranging from solar energy collection, to flat panel displays, for example like that described in patent application U.S. 60/659,498, which is hereby incorporated by reference.
The “collection angle” refers to the range of angles from which light enters a CPC and is able to successfully exit the CPC without being reflected due to total internal reflection (TIR). One issue of CPC design that is relevant to all of these applications is that it is desirable to increase the collection angle. For solar energy applications, an increase in the collection angle can increase the efficiency of the system. For flat panel displays, viewing angle, contrast ratio, and overall brightness can be improved as a result of increasing the collection angle